The present invention relates to model aircraft and has particular reference to fuel tanks therefor.
Fuel tanks in wide use in today's model aircraft generally comprise a fuel container of plastic, such as polyethelene, to which fuel feed and air vent lines are connected. The fuel line usually includes a short length of flexible brass tubing which passes through an elastomeric stopper in a central opening in one end of the tank to which is connected a length of flexible tubing within the container. The end of the flexible tubing is weighted so that it follows and is submerged in the main body of the liquid fuel in all attitudes and accelerations of the aircraft.
Sullivan in U.S. Pat. No. 3,679,092 discloses a design which includes an obliquely angled tank wall portion designed to slant the stopper in order to facilitate mounting. Venting in Sullivan is accomplished by the addition of one or more rigidly angled vent lines protruding through the stopper into the tank body. Assembly of this device requires careful manipulation of the vent lines through the stopper opening and time consuming adjustments to make sure the vent lines are properly oriented.
Another available device includes the Kraft Hayes fuel tank which, although it eliminates the need for wriggling vent lines through the tank opening, provides no venting when the tank is in an inverted position. The Kraft Hayes unit also requires a precision tank opening to accommodate a metallic stopper fitting.
Metallic components, as used in both prior art devices have been found to be undesirable. Aside from adding unnecessary costs to the product, metallic parts tend to corrode badly in the presence of the typical model fuel mixtures used.
In my invention only a single plastic fuel line pierces the stopper. Vents are provided by a pair of nipples forming an integral portion of the tank wall, and protruding from the ends of tank, one nipple being near the top of the tank and the other being near the bottom of the tank. The upper nipple is connected to the atmosphere by tubing which leads to the outside of the aircraft through the bottom of the craft; the lower nipple is connected to tubing which leads to the atmosphere through the upper surface of the aircraft. Thus, the space above the liquid fuel will be vented to the atmosphere no matter where the aircraft is flying upright or inverted.
All metallic components have been eliminated thereby minimizing weight, cost and corrosion problems while providing a simple, durable and reliable fuel tank system.
It is, therefore, a principle object of the present invention to provide an improved model aircraft fuel tank which overcomes many of the problems of the prior art.
It is a more particular object of the present invention to provide an easily assembled fuel tank which can function reliably regardless of its angular orientation.
It is a further object of the present invention to provide a lightweight and inexpensive fuel tank which lends itself to mass production techniques and omits corrodible metallic parts.
These and other objects and advantages of the present invention are accomplished in the preferred embodiment of the invention by providing a fuel tank device having a molded fuel tank body having integral upper and lower vent nipples with a central aperture therebetween. A forward extension may also be included in the molded body to prevent shifting of the tank while permitting maximum fuel capacity.
Fuel tank stopper means have also been provided which require no manipulation to install and avoids the use of corrodible metallic parts.
Further aspects of the invention will become apparent from the following description taken in conjunction with the illustrated embodiments in the accompanying drawings.